Install Google Authenticator software on the server

Execute the Google Authenticator software on the server

This authenticator must be executed using the account that will be used to login in the system; if there are multiple
accounts, it must be executed once per account.

google-authenticator

This asks several questions -all should be answered with yes-, and will display a QR code that can be loaded directly on the smartphone app,
together with the secret key, verification code and emergency scratch codes.

To configure the app, load the QR on the phone, or enter alternatively the provided secret key